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    <div class="refentry" id="glTransformFeedbackVaryings">
      <div class="titlepage"/>
      <div class="refnamediv">
        <h2>Name</h2>
        <p>glTransformFeedbackVaryings — specify values to record in transform feedback buffers</p>
      </div>
      <div class="refsynopsisdiv">
        <h2>C Specification</h2>
        <div class="funcsynopsis">
          <table style="border: 0; cellspacing: 0; cellpadding: 0;" class="funcprototype-table">
            <tr>
              <td>
                <code class="funcdef">void <strong class="fsfunc">glTransformFeedbackVaryings</strong>(</code>
              </td>
              <td>GLuint <var class="pdparam">program</var>, </td>
            </tr>
            <tr>
              <td> </td>
              <td>GLsizei <var class="pdparam">count</var>, </td>
            </tr>
            <tr>
              <td> </td>
              <td>const char ** <var class="pdparam">varyings</var>, </td>
            </tr>
            <tr>
              <td> </td>
              <td>GLenum <var class="pdparam">bufferMode</var><code>)</code>;</td>
            </tr>
          </table>
          <div class="funcprototype-spacer"> </div>
        </div>
      </div>
      <div class="refsect1" id="parameters">
        <h2>Parameters</h2>
        <div class="variablelist">
          <dl class="variablelist">
            <dt>
              <span class="term">
                <em class="parameter">
                  <code>program</code>
                </em>
              </span>
            </dt>
            <dd>
              <p>
                    The name of the target program object.
                </p>
            </dd>
            <dt>
              <span class="term">
                <em class="parameter">
                  <code>count</code>
                </em>
              </span>
            </dt>
            <dd>
              <p>
                    The number of varying variables used for transform feedback.
                </p>
            </dd>
            <dt>
              <span class="term">
                <em class="parameter">
                  <code>varyings</code>
                </em>
              </span>
            </dt>
            <dd>
              <p>
                    An array of <em class="parameter"><code>count</code></em> zero-terminated strings specifying the
                    names of the varying variables to use for transform feedback.
                </p>
            </dd>
            <dt>
              <span class="term">
                <em class="parameter">
                  <code>bufferMode</code>
                </em>
              </span>
            </dt>
            <dd>
              <p>
                    Identifies the mode used to capture the varying variables when transform feedback is active.
                    <em class="parameter"><code>bufferMode</code></em> must be <code class="constant">GL_INTERLEAVED_ATTRIBS</code> or <code class="constant">GL_SEPARATE_ATTRIBS</code>.
                </p>
            </dd>
          </dl>
        </div>
      </div>
      <div class="refsect1" id="description">
        <h2>Description</h2>
        <p>
            The names of the vertex or geometry shader outputs to be recorded in transform feedback mode
            are specified using <code class="function">glTransformFeedbackVaryings</code>. When a geometry shader
            is active, transform feedback records the values of selected geometry shader output variables
            from the emitted vertices. Otherwise, the values of the selected vertex shader outputs are
            recorded.
        </p>
        <p>
            The state set by <code class="function">glTranformFeedbackVaryings</code> is stored and takes effect
            next time <a class="citerefentry" href="glLinkProgram.xhtml"><span class="citerefentry"><span class="refentrytitle">glLinkProgram</span></span></a> is called
            on <em class="parameter"><code>program</code></em>. When <a class="citerefentry" href="glLinkProgram.xhtml"><span class="citerefentry"><span class="refentrytitle">glLinkProgram</span></span></a>
            is called, <em class="parameter"><code>program</code></em> is linked so that the values of the specified varying variables
            for the vertices of each primitive generated by the GL are written to a single buffer
            object if <em class="parameter"><code>bufferMode</code></em> is <code class="constant">GL_INTERLEAVED_ATTRIBS</code> or multiple
            buffer objects if <em class="parameter"><code>bufferMode</code></em> is <code class="constant">GL_SEPARATE_ATTRIBS</code>.
        </p>
        <p>
            In addition to the errors generated by <code class="function">glTransformFeedbackVaryings</code>, the
            program <em class="parameter"><code>program</code></em> will fail to link if:
            </p>
        <div class="itemizedlist">
          <ul class="itemizedlist" style="list-style-type: disc; ">
            <li class="listitem">
              <p>
                        The count specified by <code class="function">glTransformFeedbackVaryings</code> is non-zero, but the
                        program object has no vertex, tesselation evaluation, or geometry shader.
                    </p>
            </li>
            <li class="listitem">
              <p>
                        Any variable name specified in the <em class="parameter"><code>varyings</code></em> array is not declared as a 
                        built-in or user-defined output in the shader stage whose outputs can be recorded.
                    </p>
            </li>
            <li class="listitem">
              <p>
                        Any two entries in the <em class="parameter"><code>varyings</code></em> array specify the same varying variable.
                    </p>
            </li>
            <li class="listitem">
              <p>
                        The total number of components to capture in any varying variable in <em class="parameter"><code>varyings</code></em>
                        is greater than the constant <code class="constant">GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS</code>
                        and the buffer mode is <code class="constant">GL_SEPARATE_ATTRIBS</code>.
                    </p>
            </li>
            <li class="listitem">
              <p>
                        The total number of components to capture is greater than the constant
                        <code class="constant">GL_MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS</code> and the buffer
                        mode is <code class="constant">GL_INTERLEAVED_ATTRIBS</code>.
                    </p>
            </li>
          </ul>
        </div>
        <p>
        </p>
      </div>
      <div class="refsect1" id="errors">
        <h2>Errors</h2>
        <p>
            <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>program</code></em> is not
            the name of a program object.
        </p>
        <p>
            <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>bufferMode</code></em> is <code class="constant">GL_SEPARATE_ATTRIBS</code>
            and <em class="parameter"><code>count</code></em> is greater than the implementation-dependent limit <code class="constant">GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_ATTRIBS</code>.
        </p>
      </div>
      <div class="refsect1" id="associatedgets">
        <h2>Associated Gets</h2>
        <p>
            <a class="citerefentry" href="glGetTransformFeedbackVarying.xhtml"><span class="citerefentry"><span class="refentrytitle">glGetTransformFeedbackVarying</span></span></a>
        </p>
      </div>
      <div class="refsect1" id="versions">
        <h2>API Version Support</h2>
        <div class="informaltable">
          <table style="border-collapse: collapse; border-top: 2px solid ; border-bottom: 2px solid ; border-left: 2px solid ; border-right: 2px solid ; ">
            <colgroup>
              <col style="text-align: left; "/>
              <col style="text-align: center; " class="firstvers"/>
              <col style="text-align: center; "/>
              <col style="text-align: center; "/>
              <col style="text-align: center; " class="lastvers"/>
            </colgroup>
            <thead>
              <tr>
                <th style="text-align: left; border-right: 2px solid ; ">
                 
            </th>
                <th style="text-align: center; border-bottom: 2px solid ; " colspan="4">
                <span class="bold"><strong>OpenGL ES API Version</strong></span>
            </th>
              </tr>
              <tr>
                <th style="text-align: left; border-right: 2px solid ; border-bottom: 2px solid ; ">
                <span class="bold"><strong>Function Name</strong></span>
            </th>
                <th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
                <span class="bold"><strong>2.0</strong></span>
            </th>
                <th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
                <span class="bold"><strong>3.0</strong></span>
            </th>
                <th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
                <span class="bold"><strong>3.1</strong></span>
            </th>
                <th style="text-align: center; border-bottom: 2px solid ; ">
                <span class="bold"><strong>3.2</strong></span>
            </th>
              </tr>
            </thead>
            <tbody>
              <tr>
                <td style="text-align: left; border-right: 2px solid ; ">glTransformFeedbackVaryings</td>
                <td style="text-align: center; border-right: 2px solid ; ">-</td>
                <td style="text-align: center; border-right: 2px solid ; ">✔</td>
                <td style="text-align: center; border-right: 2px solid ; ">✔</td>
                <td style="text-align: center; ">✔</td>
              </tr>
            </tbody>
          </table>
        </div>
      </div>
      <div class="refsect1" id="seealso">
        <h2>See Also</h2>
        <p>
            <a class="citerefentry" href="glBeginTransformFeedback.xhtml"><span class="citerefentry"><span class="refentrytitle">glBeginTransformFeedback</span></span></a>,
            <a class="citerefentry" href="glEndTransformFeedback.xhtml"><span class="citerefentry"><span class="refentrytitle">glEndTransformFeedback</span></span></a>,
            <a class="citerefentry" href="glGetTransformFeedbackVarying.xhtml"><span class="citerefentry"><span class="refentrytitle">glGetTransformFeedbackVarying</span></span></a>
        </p>
      </div>
      <div class="refsect1" id="Copyright">
        <h2>Copyright</h2>
        <p>
            Copyright <span class="trademark"/>© 2010-2015 Khronos Group.
            This material may be distributed subject to the terms and conditions set forth in
            the Open Publication License, v 1.0, 8 June 1999.
            <a class="link" href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>.
        </p>
      </div>
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